I just did a quick google. The ratio in NSW is different from many other states, and there only need be 1 early childhood educator for a group of 30 - 39 students. Actually, the wording is 'at least one'. I personally believe from an educator/behaviour management of view, that this is completely insufficient.
As a comparison, the ratio in Qld is 1:15. In Victoria it's 1:15 (educator, not adults). In WA the recommended maximum class size is between 20 and 25 students depending on the class (ie purely kindy or Kindy/Yr 1).